Sugar cane crushing mills



Sept. 17, 1963 w, M, LME 3,103,874

SUGAR CANE CRUSHING MILLS Filed Oct. 18, 1961 3 Sheets-Sheet l W. M.LIVIE SUGAR CANE CRUSI-IING MILLS Sept. 17, 1963 3 Sheets-Sheet 2 Filed00%. 18, 1961 p 7 1963 w. M. LlVlE 3,103,874

SUGAR CANE CRUSHING MILLS Filed Oct. 18, 1961 3 Sheets-Sheet 3 UnitedStates Patent 1a is 3,103,874 SUGAR CANE CRUSHING MILLS William MarshallLivie, 24 Ponsonby Parade, Seaforth, New South Wales, Australia Fiied0st. 18, 1961, Ser. No. 145,825 Claims priority, application AustraliaOct. 31, 1960 12 Claims. (Cl. lt)075) This invention relates tomulti-twin and multi-tr-iple roller mills for crushing sugar cane forextracting the juice or sucrose.

The object of the invention is to provide a mill mechanically moreeflicient, which has a relative higher rate of crushing, is highlyeflicient, and is less expensive to install and operate thanconventional twoor three-roller mills.

For example, under comparable conditions, the rate of crushing withmills according to the present invention is more than twice that withorthodox mills.

Due to the short distance between the centres of each pair of rolls (sayapproximately 9 feet) a much shorter building would sufiice toaccommodate a multi-twin roller crushing unit than is required forexisting three roller mills with diffusion baths and inter mediatecarriers disposed between each crushing unit. Also due to the relativelyhigher rate :of work, comparatively, the width of roller would be lessthan is commonly now in use.

Cost features in the above greatly favour multi twin roller crushingunits.

In a general form the invention is a sugar cane crushing mill comprisingat least two spaced sets of crushing rollers, first means includingspaced conveyors diverging forwards for feeding prepared came to theinlet side of the first set of rollers, a first closed chute on theoutlet side of each set of rollers adapted to receive the crushed canefrom the adjacent set, second means including a second closed chutediverging forwards at approximately for feeding crushed cane from eachfirst closed chute to the next set of rollers, means for turning overthe crushed cane at least partially during its passage from one set ofrollers to the next and means for collecting expressed juice from thecane during and after its passage through each set of rollers.

By a closed chute is meant one which is closed at its top, bottom andsides. It is open at one end to receive crushed :cane from the previousset of rollers and at its other end to allow crushed cane to passtowards the next set of rollers.

Some specific forms of the invention are shown in the accompanyingdrawings in which:

FIGURE 1 is a part perspective view of one form of the invention withsome parts omitted for clarity;

FIGURE 2 shows an alternative means for feeding prepared cane to thefirst set of rollers;

FIGURE 3 is a view similar to that of FIGURE 1 but employing triple-rollsets instead of twin-roll sets;

FIGURE 4 is a typical vertical section at the left of the first set ofrollers;

FIGURES 5 and 6 are detail views slatted belt constructions;

FIGURES 7, 8- and 9 are detail views of alternative roll axle spacingmeans;

FIGURE 10 is a detail view of roll grooving;

FIGURE 11 is a detail showing the rolls and juice trough arrangement;

FIGURES 12 and 13 are detail views of flanged and side-plated rolls;

FIGURE 14 is a detail of a grooved roll and associated scraper plate;

FIGURES l5 and 16 are detail views of a roll with juice grooves and anassociated juice groove scraper;

FIGURE 17 is a fragmentary longitudinal sect-ion showof alternative inga cane chute with fixed floor and a fixed and moving roof, and

FIGURE 18 is similar to FIGURE 17 but shows also means for feedingmacerating fluid.

FIGURE 1 shows a typical arrangement of multitwin rollers with a bandconveyor feed 21, 22 to the first pair of rollers 23, 24 followed by theclosed chute slat conveyor 25 and maceration fluid pipes 26 and 27.There follow the second pair of rollers 28, 29 with a closed feed chute30 between each pair of rollers.

FIGURE 2 shows a variation of the position of the prepared cane feedbands 31, 32 in relation to the first pair of rollers. It shows thesebands inclined from the horizontal in a position to feed the preparedcane downwards and forwards to the first pair of rollers and thereafterhaving :all other aspects similar to what is shown and described forFIGURE 1,

FIGURE 3 shows the application of the closed chute to a typical threeroller mill 33, 34 and 35 with a short closed chute 36 provided withmaceration fluid pipes 37 on the discharge side of rollers 33' and 35set to deliver crushed cane or lbagasse upwards and forwards tomechanically driven two-band or two-slat conveyors 40, 41 feeding tofront and top rollers 42, 43 of the next three roller mill of a tandem.

A particular form of the invention will now be described having tworollers in each set disposed with their axes approximately horizontalone above the other. In this particular case there are four pairs ofrollers (FIGS. 1 and 2) but there could be more pairs or fewer down totwo pairs of rollers.

The prepared cane, ready for crushing, is fed as in FIGURE 1horizontally and forward, or as in FIGURE 2 downwards and forwards onthe incline of a closed chute in each case formed by the forward runs oftwo spaced band conveyors 21, 22 or 31, 32 running between fixed sideplates 44 (FIGURE 4) which prevent spillage and assist in building up aslight feed pressure to the rollers. Each band has attached to its outerface spaced transverse gripping strips 45 (FIGURE 5) to assist the rateof feeding between the bands; lipped slats 46 (FIGURE 6) may be used asan alternative. The band pulleys 4-7, 48 illustrated in FIGURES 1 and 2are larger at the prepared cane entry end than those at the dischargeend. The reason for the smaller pulleys 48 at the discharge end is tobring the prepared cane as close to the crushing rolls as is possible.The bands may be driven as circumstances permit from either the entry ordischarge end pulleys.

The bands diverge slightly in a vertical plane from entry end todischarge end to avoid choir-age of the feed between the bands.

The bands are driven at speeds in excess of the surf-ace speed of thecrushing rollers to ensure a satisfactory high rate of feeding to thenip of the crushing rollers and to maintain a slight build up ofpressure of the feed against the two crushing rollers.

The roller axle spacing may be varied. This may be done by forcingbetween the roller axle bearing blocks 49, wedges 50 (FIGURE 7) orpacking piece 51 (FIG- URE 8) or by screws 52 (FIGURE 3).

Each roller is formed with axially spaced circumferential V grooves,respective crests of one roller being aligned with the troughs of theother so that, when the roller axle spacing is least, each crest of oneroller almost fills the corresponding trough of the other. In specialcircumstances and where it can be conveniently used circumferential Vgrooves may be varied. In FIG. 10, e.g. where the opening between thetop and bottom rollers 23, 24 is always positive, the groove pitch onone may differ from that on the other. Each roller is driven at aconvenient speed.

J-uice expressed from the cane (or ba'gasse) as the latter is crushedbetween the rollers is drained to a bed plate juice trough 53 (FIG. 11).The top roller of the pair of rollers should have flanges 54 (FIG. 12)fitted to its ends as this is considered an aid to good crushing.Otherwise close fitting side plates 55 (FIG. 13) at the rollers would berequired and this may be readily arranged where a mild steel fabricationis used as a frame instead of cast steel or cast iron mill cheeks.

On the exit side of the rollers there are adjustable top and bottomscraper plates 56 (FIG. 14) (part of a closed feed system to the nextpair of rollers) which have teeth 57 so cut as to fit into the groovesof the rollers and remove the crushed cane embedded in the grooves. Thebottom rollers 24 have narrow juice grooves 58 (FIG. 16) cut at thebottom of the V grooves to assist extraction of juice and these groovesare. kept clean by fixed knife scrapers 59 (FIG.

The crushed cane with less sugar juice now passes through a closed chutediverging at approximately 5 farwardly, the top plate 56 of which is cutshort to provide for a mechanically driven lipped slat conveyor againdriven through either a large diameter rearward pulley or a smallerforward pulley for similar reasons as stated for the band conveyors 21,22 in FIG. 1. This conveyor 25 runs at a slightly higher speed than theperipheral speed of the crushing rollers 28, 29 it is feeding. The band25 on its lower run travels horizontally and its use is designed to movethe crushed cane at the top of the chute along to the next pair of rollsat a faster rate than the main body of the crushed cane or bagasse. Thefixed bottom plate 60A is stepped down at 60 (FIG. 17) to delay furtherthe forward movement of the lower crushed cane compared to the main bodyof crushed cane orbagasse between the upper and lower layers. Where thesets of rollers are widely spaced two or more spaced steps 60 may beprovided. This speed variation through the cross section of the mass ofcrushed cane or bagasse re-orients the crushed cane or bagasse fibre atthe top and bottom of the cross section in each closed chute to the nextpair of rollers and thus assists the further extraction of juice orsucrose. In its passage through the closed chute between successive setsof rollers, the mass of bagasse is reduced in density by being teasedout and reoriented by the relatively high speed upper band 25 and thestepped chute floor.

It has been found by experiment that further extraction of juice fromthe teased bagasse as it passes through the next set of rollers isgreater than if the bagasse had remained in a compact high densitycondition.

In some circumstances the fixed stepped plate 69A may be dispensed withand a lower conveyor, generally similar to the upper conveyor 25,substituted. This arrangement is similar to that of FIG. 3.

Provision is made for the application of macerating fluids underpressure through a V channel 61 (FIG. 18) cut across the inside surfacesof the top plate 56, bottom plate 60A and both side plates 64 of theclosed chute and the maceration pipes 26, 27 are connected externallythrough suitable holes to the V grooves. This provision is designed sothat a comparatively low density fluid may penetrate at least the outerlayer of the crushed cane passing along the chute.

Experiments have shown that the outside of the crushed cane from therollers contains higher density juice than the inner section of thecrushed cane. The dilution effected assists the extraction of sucroseduring crushing between the rollers.

The crushed cane (generally known as bagasse) passes successivelythrough a second pair of rollers similar and similarly mounted anddriven to .the first pair, through a similar chute with fixed sides andfloor (stepped) and having a fixed roof at its rearward end and a movingroof at its forward end as before and then to the next pair of rollersand so on.

Where convenient conventional sets of existing three roller units may beretained and the closed feed system installed (FIG. 3) between each setof three rollers. There are two horizontally spaced rollers 34, 35 andone upper one 33 between the lower two. The cane passes between theupper roller 33 and the rearward lower roller 34 and between the upper33 and the forward lower roller 35. A narrow trash plate 65 extends be-.tween the lower rollers over which the cane or bagasse passes. Thechute 36 is closed at its top, bottom and sides.

This arrangement, whilst making use of existing crushing rollers, wouldnot have all of the advantages outlined above for multi-twin rollers.

Experiments with a small multi-twin roller crushing unit resulted in acane fibre rate of nearly 5.0 tons per foot width of roller per hour(t.f.f.h). Had more power for driving been available a much higher ratewould have been attained.

Previous experiments with a small experimental crushing unit showed thatthe fibre rate attained was more than doubled when large commercialcrushing units were manufactured and installed.

A similar relationship would no doubt exist between this smallmulti-twin roller plant and a larger commercial unit and if realised acane fibre rate of 10.0 t.f.f.h. or more could be expected.

The high rate of work combined with high efficiency of operation wouldenable the cost of construction of cane sugar mills :to be greatlyreduced as the length of the rollers and diameter of shaft hearingswould be much less than currently required for three roller mills andlabour and production costs would be considerably reduced.

The number of rollers in use at present in most crushing stations ofcane sugar factories could be reduced by the use of multi-twin rollercrushing mills thereby lowering capital cost and maintenance.

What I claim is:

1. A sugar cane crushing mill comprising at least two spaced sets ofcrushing rollers for feeding crushed cane through said rollers, firstmeans for feeding prepared cane adapted for being crushed to the firstset of rollers, the latter means including spaced moving conveyorsdiverging in the direction of feedof the cane towards the rollers andhaving a linear speed exceeding the peripheral speed of the rollers tocause the prepared cane to be fed under pressure to the first set ofrollers, each set of rollers having an inlet and an outlet side, aclosed chute on the outlet side of each set of rollers for receivingcrushed cane from the associated set, each closed chute diverging fromthe outlet side of the associated set of rollers in a direction awaytherefrom, second means including a second closed chute between each ofthe first said closed chutes and the next set of rollers for receivingcrushed cane from the first closed chute for feeding the crushed cane tothe next set of rollers while reorienting and teasing out the crushedcane, said second means including a conveyor in said second closed chutehaving a linear speed in a direction towards the next set of rollerswhich is greater than the peripheral speed of the rollers, for advancinga surface layer of the crushed cane which is in contact with the latterconveyor at an increased speed towards the next set of rollers, adjacentfirst and second chutes defining a step opposite the conveyor in saidsecond closed chute for increasing the section of travel of the crushedcane whereby the advance of the crushed cane in a surface layer oppositethe first said surface layer will be decreased as the crushed canepasses said step, the mill further comprising means for collectingexpressed juice from the cane during and after passage thereof througheach set of rollers.

2. A mill as in claim 1 wherein the first feeding means comprises spacedside walls forming with the said spaced diverging conveyors anothersubstantially closed chute and means for driving the conveyors so thatthe same advance towards the first set of rollers.

3. A mill as in claim 2 wherein the said conveyors of the first meansare approximately horizontal.

4. A mill as in claim 2 wherein the said conveyors of the first meansslope downwards towards the first set of rollers.

5. A mill as in claim 1 wherein the rollers of each set are providedwith circumferential grooves and at least one scraper plate for eachroller on the outlet side thereof, each plate having an edge adjacentthe roller provided with spaced teeth adapted to enter the respectiveroller grooves to scrape the same.

6. A mill as in claim 5 wherein one scraper plate is provided for eachroller on .the outlet side of the set and the scraper plates form therespective top and bottom walls of the first closed chute.

7. A mill as in claim 5 wherein narrow juice grooves are provided at thebottom of the main grooves of the bottom roller on the outlet side ofthe set and a knife scraper having spaced teeth adapted to enter therespective juice grooves to clean the same.

8. A mill as claimed in claim 1 wherein the second chutes each have aroof constituted by said conveyor thereof, adjacent first and secondchutes including a stationary continuous floor extending along bothchutes and including said step which is located below the conveyor ofthe second means at the beginning thereof such that an upper surfacelayer of the crushed cane is moved more rapidly than the remainder ofthe crushed cane and a lower surface layer of the crushed cane is movedmore slowly than the remainder of the crushed cane whereby the crushedcane undergoes a turning over and reorientation.

9. A mill as in claim 1 wherein the second closed chute has a roof andfloor between adjacent sets of rollers, the lower run of an upper bandconveyor and the upper run of a lower band conveyor respectivelyconstituting the roof and floor of the second closed chute, the saidlower run being spaced above the said upper run, the latter conveyorsextending between the associated first closed chute and the next set ofrollers and means for driving the said conveyors so that the said lowerand upper runs move towards the next set of rollers, the conveyorscomprising means for turning over the crushed cane.

10. A mill as in claim 9 wherein the roof and floor of the second closedchute between adjacent sets of rollers diverge towards the next set ofrollers in an approximately vertical plane.

11. A mill as in claim 1 including means for feeding macerating fluid toeach first closed chute.

'12. A mill as in claim 1 wherein the two sides of each set of rollers:are closed to provide a substantially closed passage for the canethrough each set of rollers.

References Cited in the file of this patent UNITED STATES PATENTS

1. A SUGAR CANE CRUSHING MILL COMPRISING AT LEAST TWO SPACED SETS OFCRUSHING ROLLERS FOR FEEDING CRUSHED CANE THROUGH SAID ROLLERS, FIRSTMEANS FOR FEEDING PREPARED CANE ADAPTED FOR BEING CRUSHED TO THE FIRSTSET OF ROLLERS, THE LATTER MEANS INCLUDING SPACED MOVING CONVEYORSDIVERGING IN THE DIRECTION OF FEED OF THE CANE TOWARDS THE ROLLERS ANDHAVING A LINEAR SPEED EXCEEDING THE PERIPHERAL SPEED OF THE ROLLERS TOCAUSE THE PREPARED CANE TO BE FED UNDER PRESSURE TO THE FIRST SET OFROLLERS, EACH SET OF ROLLERS HAVING AN INLET AND AN OUTLET SIDE, ACLOSED CHUTE ON THE OUTLET SIDE OF EACH SET OF ROLLERS FOR RECEIVINGCRUSHED CANE FROM THE ASSOCIATED SET, EACH CLOSED CHUTE DIVERGING FROMTHE OUTLET SIDE OF THE ASSOCIATED SET OF ROLLERS IN A DIRECTION AWAYTHEREFROM, SECOND MEANS INCLUDING A SECOND CLOSED CHUTE BETWEEN EACH OFTHE FIRST SAID CLOSED CHUTES AND THE NEXT SET OF ROLLERS FOR RECEIVINGCRUSHED CANE FROM THE FIRST CLOSED CHUTE FOR FEEDING THE CRUSHED CANE TOTHE NEXT SET OF ROLLERS WHILE REORIENTING AND TEASING OUT THE CRUSHEDCANE, SAID SECOND MEANS INCLUDING A CONVEYOR IN SAID SECOND CLOSED CHUTEHAVING A LINEAR SPEED IN A DIRECTION TOWARDS THE NEXT SET OF ROLLERSWHICH IS GREATER THAN THE PERIPHERAL SPEED OF THE ROLLERS, FOR ADVANCINGA SURFACE LAYER OF THE CRUSHED CANE WHICH IS IN CONTACT WITH THE LATTERCONVEYOR AT AN INCREASED SPEED TOWARDS THE NEXT SET OF ROLLERS, ADJACENTFIRST AND SECOND CHUTES DEFINING A STEP OPPOSITE THE CONVEYOR IN SAIDSECOND CLOSED CHUTE FOR INCREASING THE SECTION OF TRAVEL OF THE CRUSHEDCANE WHEREBY THE ADVANCE OF THE CRUSHED CANE IN A SURFACE LAYER OPPOSITETHE FIRST SAID SURFACE LAYER WILL BE DECREASED AS THE CRUSHED CANEPASSES SAID STEP, THE MILL FURTHER COMPRISING MEANS FOR COLLECTINGEXPRESSED JUICE FROM THE CANE DURING AND AFTER PASSAGE THEREOF THROUGHEACH SET OF ROLLERS.